My dilemma – my hinging skills stink. I have hinged several ARFs (SIG Kadet Senior, Goldberg Tiger 2 and Hobbico Avistar). I have hinged several kits (SIG 4Star60, SIG Kadet Senior and 2 SIG Somethin’ Extras). I have focused on a single type of hinge – the Dubro nylon standard hinge using 30-minute epoxy. The results have been inconsistent. The width of the hinge line has been too wide IMHO. The ease of movement of the control surface has been inconsistent. The covering of the hinge slots have been sloppy & loose. The pre-covered slots look like they were done by a drunken sailor. Bottom line, I wanted to solve this hinging dilemma.

My Goal: Be able to consistently install Dubro’s nylon pinned hinges resulting in a tight straight hinge line that covers well and doesn’t drive me to profanity.

After having struggled through cutting elevator & rudder hinges on my current 4Star60 kit I took a trip to the LHS of our local building guru. He’s the one that has kept telling me how “simple” hinge installation is! I took my tools and scrap balsa to his store and threw them on the counter with a Dubro hinge. I said something like “OK wise guy, if it’s so darn simple SHOW ME!” - smiling of course. My tools included: Xacto #1 handle with Xacto #11 blade, Xacto #1 handle with Xacto #13 micro saw blade and 1 Xacto #5 heavy duty handle with Xacto #17 keyhole saw blade.

His first observation was that the kerf of the #17 keyhole saw blade was too narrow for the Dubro standard hinge. He guessed that I had to expand the hole freehand to open the slot wide enough. Freehand cutting will result in inconsistent (aka sloppy) slots. He grabbed a Xacto #27 heavy duty saw blade. The kerf of this blade is just right for the width of the Dubro hinge.

He then grabbed my scrap balsa and using my tools quickly cut the slot, dropped the hinge in with the pin flush with the surface and said “what’s the big deal?”. I felt a tear coming.

I took his technique home (with a bunch of new #27 heavy duty blades), tossed the wing on the table (12 hinge slots needed), and cut 12 (nearly) identical slots in the wing all in alignment and all of the pins sitting flush with the trailing edge in maybe 20 minutes with no stress.

Here’s the tool list:
2 Xacto #1 handles (1 will do)
2 Xacto #5 handles (1 will do)
1 Xacto #11 blade
1 Xacto #13 micro saw blade
1 Xacto #17 keyhole saw blade (#5 handle)
1 Xacto #27 heavy duty saw (#5 handle) and
1 90 degree angle.

Here’s the sequence:
1. transfer hinge end points from the plans to the surface with 90 degree angle and pencil;
2. cut a straight centered slot between the end points with #11 blade - deep enough for the hinge
3. end-cut the slots with #11 blade (to make nice bevel angles plunge the blade into the slot end-point with the blade towards the outside of the surface – requires 4 cuts for each slot)
4. clear slot with #13 micro saw blade
5. widen slot with #17 keyhole saw
6. widen slot with #27 heavy duty saw (if you skip using #17 – the slot can get sloppy quickly)
7. bevel cut the slot with #11 blade
repeat steps 2 through 7 until done
lightly sand

Pic 1: Dubro hinges
Pic 2: Tools
Pic 3: slot end points marked on surface
Pic 4: start slot freehand
Pic 5: finish cutting slot full depth
Pic 6: end-cut slot
Pic 7: clear slot micro saw
Pic 8: open slot keyhole saw
Pic 9: not enough clearance
Pic 10: open slot heavy duty saw
Pic 11: ditto
Pic 12: hinge in un-beveled slot

Next Post (too many pics for 1 post)
Pic 1: bevel slot
Pic 2: finished slot (unless you want to sand it)
Pic 3: hinge in beveled slot
Pic 4: ditto
Pic 5: finished aileron hinge line
Pic 6: ditto

HTH!

Continuation of post 1 ...
I added the final picture. It is the aileron hinge line using dubro standard hinges as built by my LHS guru. That's my build quality goal.

Looks good. Have you tried using the hinges with removable cotter pins instead of fixed pins? You could then use a single long wire to join all of the hinges. That way you could remove the control surface for rework/recovering if needed without having to destroy the hinges.

Just a thought.

I use a #11 blade exclusively.
Have done for years.
Might actually try the saw blade approach, if it makes it faster.

One more step to perform as a suggestion: After you locate and mark the slot end point's, drill a small diameter hole @ these endpoint locations. This is termed "Stop Drilling", and it prevents a split /crack / slit from continuing along it's path. Maybe overkill for modeling, but then again...maybe not.

I built the Tamiya Drill and keep a small bit ( 1/16" ) in it just for this purpose.

http://www3.towerhobbies.com/cgi-bin...?&I=LXRK17&P=7

In welding, if you don't stop drill a crack, you can grind the material down to china, weld it like you were plating a ship...but eventually...the original crack will grow out (continue along it's original path) underneath the weld.